International Winter Wheat nurseries data: Facultative and Winter Wheat Observation Nurseries and International Winter Wheat yield trials for semi-arid and irrigated conditions

This data paper describes the content of 16 datasets collected under the International Winter Wheat Improvement Program (IWWIP), an alliance between Turkey-CIMMYT-ICARDA (TCI), during the 2015–2016, 2016–2017, 2017–2018 and 2018–2019 seasons. Data was collected from the Facultative and Winter Wheat Observation Nursery (FAWWON) and the International Winter Wheat Yield Trials (IWWYT) conducted under semi-arid and irrigated conditions across different countries. Data on all nurseries was collected during the growing season by IWWIP's team and cooperators in their local environments. It was compiled at the end of the wheat season by IWWIP's team. Multi-locational data can be used to select advanced lines that fit to collaborators’ growing environment. The selected germplasm can either be used as a parent in their breeding programs or be released as a variety in their country.

Data on all nurseries was collected during the growing season by IWWIP's team and cooperators in their local environments. It was compiled at the end of the wheat season by IWWIP's team. Multi-locational data can be used to select advanced lines that fit to collaborators' growing environment. The selected germplasm can either be used as a parent in their breeding programs or be released as a variety in their country.  Table   Subject  Agronomy and Crop Science  Specific subject area  Winter wheat improvement, germplasm exchange  Type of data  Tables  Biplots  How data were acquired • Data for genotypes/advanced lines in multi-locations, yields, disease screening and traits were collected by IWWIP's team and local cooperators through field trials and laboratory screenings. • The Molecular Markers study was outsourced to a private company.
• The yield and ranking biplots were made using Genstat software.

Data format
Tables in CSV files Biplots in PNG and Pdf files Parameters for data collection Parameters for data collection are not always standardized among the cooperators, particularly field measurements and observation data, as each cooperator might use different evaluation scales or data collection methods. All relevant details are described thoroughly in the CSV file "DataDictionary_ElementDescription" of each dataset.

Description of data collection
The data was collected by IWWIP's team and cooperators at local level each with their personnel and labor organization. Data compilation was performed by IWWIP's team. Data source location The data was collected by IWWIP's team and cooperators at local level. A detailed list of the cooperators involved in the experiment is provided in the CSV file "Cooperators" of each dataset. The file also includes the coordinates of each research station. The cooperators operate in the following countries:

Value of the Data
• The experiments are conducted in multiple locations and in diverse growing environments providing information on the performance of the genotypes tested in those environments including disease resistance, quality attributes and molecular data in some years. The collected data is free for use by breeding programs and breeders for their evaluations and decisions on genotypes. • The breeding and research programs, which are cooperators in IWWIP and obtain germplasm from IWWIP, benefit greatly through access to the data on germplasm that has been generated over diverse regions and environments. • In general, the observation nurseries are targeted to identify adapted genotypes that can be potentially used as parents in the breeding programs of the corresponding NARS, while the yield trials are primarily distributed to identify widely adapted genotypes to be released in the corresponding countries and to be used in future crosses at IWWIP. Multi-locational data can be used to select advanced lines that fit to their growing environment. The selected germplasm can be used as a parent in breeding programs or be released as a variety in the corresponding country. Datasets IWWYT-SA and IWWYT-IRR contain the data collected from the International Winter Wheat Yield Trial (IWWYT) trials conducted under semi-arid and under irrigated conditions, respectively ( Figs. 1 and 2 ).

Data Description
The link provided with each dataset (referring to the specification table) redirects the user to a series of data files. These are presented either in CSV format (in the case of tables), or PNG and Pdf formats (in the case of biplots). A summary of the data files content is found in Table 1 .

Experimental Design, Materials and Methods
Based on the yield trial performance, short stature high-yielding germplasm developed by IWWIP and contributed by the cooperators is included into FAWWON for irrigated environments. Whereas entries with resistance to moisture stress are included in FAWWON for semiarid environments. The germplasm in this nursery may have variable height and some tall lines may also be included.
In addition, each year interested breeding programs submit their new cultivars and advanced breeding lines to IWWIP for inclusion into international testing. Once in Turkey, the material goes through quarantine inspection before being planted for primary evaluation on small plots in locations highly conducive to the key diseases. Germplasm with disease resistance and general adaptation traits is multiplied and yield-tested during a second year.
The next step is selecting the elite germplasm proven to perform well in FAWWON to be included in IWWYT. The objective of this nursery is to identify broadly adapted high-yielding germplasm, which can be potentially used as cultivars and parent material [1] .
In IWWYT, the genotypes in each trial were planted using alpha lattice design in two replications in a plot size of 5 m length, six rows with 0.2 m spacing between rows. FAWWONs are planted as 1 m two rows with checks every 20.
Data on all nurseries is collected during the growing season by IWWIP's team and cooperators in their local environments. Cooperators use either hardcopy sheets or more recently electronic files. At the end of the wheat season, the data is assembled by IWWIP's team in Ankara in a single spreadsheet and made available on IWWIP's website. The datasets described in this article were curated by ICARDA's Data Management Team, following the standards of the General Dataset Curation Guide (GDCG) [2] and subsequently published through DataverseMEL.

Declaration of Competing Interest
The authors declare that they have no known competing financial interests or personal relationships which have or could be perceived to have influenced the work reported in this paper.